Allergic reactions can be dramatic and frightening for pets and pet owners. But, knowing how to recognize and respond to your pet’s acute and alarming irritation can help you stay calm and in control when the bugs bite, the bees sting, or something else sends your pet’s internal defenses into overdrive.

While minor allergic reactions often subside on their own, severe reactions can trigger life-threatening anaphylactic shock. Immediately contact the Animal Hospital of Parkland if your pet is having difficulty breathing, has collapsed, or is unresponsive.

What is an allergic reaction in pets?

Your pet’s immune system is designed to protect their body from harmful foreign substances and microorganisms by mounting a protective response. Acute (i.e., sudden) allergic reactions occur when the immune system overreacts or is hypersensitive to a specific irritant, such as an insect bite or sting, medications, food proteins, or vaccines. Once the pet is exposed, their immune system flags the irritant as a threat and builds an aggressive defense ready for the next encounter. When the body is next exposed to the perceived threat (i.e., the pet is stung again or receives a booster vaccine), the immune system releases chemicals that most notably create local or generalized swelling. 

What causes acute allergic reactions in pets?

Like humans, pets can be sensitive to a number of natural and man-made substances in their environment, and a substance may trigger one pet’s immune system, yet be recognized as neutral and harmless by another’s.

 The most common allergic reaction triggers in pets include:

  • Insect bites and stings
  • Pollen and grasses
  • Vaccine preservatives and enhancers (i.e., adjuvants)
  • Food proteins
  • Medications
  • Over-the-counter or off-label flea and tick preventives

What is anaphylaxis in pets?

Anaphylaxis or anaphylactic shock is a response to allergen exposure and is an emergency condition. Anaphylaxis occurs almost immediately after contact with the irritant and requires equally rapid veterinary treatment to ensure the pet’s airway remains patent (i.e., free from obstruction caused by swollen tissues) and to avoid internal shock-related injury.

How can I tell if my pet is having an allergic reaction?

While runny eyes, sneezing, nasal discharge, and cough are the familiar seasonal allergy signs, acute allergic reactions appear quickly and with a range of signs that include:

  • Facial swelling, especially around the eyes, lips, and muzzle
  • Vomiting
  • Diarrhea
  • Drooling
  • Difficulty breathing (e.g., increased effort, gasping, wheezing)
  • Intense itching
  • Hives or raised bumps on the skin (i.e., wheals)
  • Lethargy
  • Blue or grey gums

Acute or anaphylactic reactions will appear almost immediately after the pet encounters the offending allergen, while milder reactions (e.g., hives) may not appear for 20 minutes or longer. 

How can I help my pet during an allergic reaction?

Your response to your pet’s allergic reaction will depend on their visible signs and their exposure type and intensity (e.g., repeated exposure to pollen versus a single bee sting). Common scenarios include:

  • If your pet is having difficulty breathing or has collapsed — Immediately take your pet to the Animal Hospital of Parkland or the nearest emergency veterinary facility for rapid care.
  • If your pet’s face is visibly swollen — We recommend contacting the Animal Hospital of Parkland. If your pet has severe swelling (i.e., cannot open their eyes) or was recently vaccinated, return to our hospital immediately.
  • If your pet is vomiting or has diarrhea — Gastrointestinal (GI) signs can cause dehydration and weakness. Notify our team if your pet is repeatedly vomiting or their stool is loose, as they may need medication and fluid therapy to prevent further illness.
  • If  your pet has localized hives or raised bumps — Local (i.e., limited to one body area) skin irritations are typically self-limiting and should improve in 24 hours. However, your pet may need treatment if their hives persist or they are extremely itchy. 
  • If your pet has multiple or worsening allergic reaction signs — These can indicate a serious reaction or anaphylactic shock. Call our team to notify us of your pet’s condition prior to your arrival.

How are allergic reactions treated in pets?

Allergic reaction treatment protocols vary depending on the pet’s condition, but generally focus on removing the irritant, securing or monitoring the pet’s airway, reducing inflammation, and monitoring vital parameters, such as blood pressure and circulation. Medications such as corticosteroids, anti-inflammatories, and antihistamines are administered as needed to reduce swelling and discomfort, and ease the respiratory system’s workload. Pets who suffer from anaphylaxis often require hospitalization and aggressive treatment to protect them against shock-related injuries.

If your pet’s allergic reaction is mild, the Animal Hospital of Parkland team may recommend that you administer diphenhydramine (i.e., Benadryl) at home. Never medicate your pet without your veterinarian’s direction.

Can allergic reactions be prevented in pets? 

A vet examines a golden retriever by gently holding its face, while a man stands by the dog's side, observing the process. The room is well-lit and appears to be a veterinary clinic.

Although you cannot prevent allergic reactions to naturally occuring irritants such as insect bites and bee stings, you can protect your pet from known allergens such as vaccines, medications, and food allergens.

If your pet’s reaction is linked to a vaccine, your veterinarian will pre-medicate your pet prior to future vaccinations. Pets with food allergies will require an elimination diet to confirm their allergy, followed by a gradual reintroduction to potential trigger foods until the allergen is identified. Seasonal allergy-related reactions may be mitigated with therapeutic shampoos, wipes, and as-needed medications.

Acute allergic reactions are alarming in appearance and intensity, but if you can recognize common allergy signs and causes, you can stay calm and ensure your pet gets appropriate care and relief. If you’re concerned that your pet is suffering from an allergic reaction or another health condition, contact the Animal Hospital of Parkland.